Normally, after manufacture, electronic components are subject to designated tests so that their electrical function is verified. For this purpose, usually a nest is attached to a stamp that moves up and down, in which nest the electronic component is precisely positioned. However, it is also known to attach several electronic components on one carrier, and to position the entire carrier in the nest.
The stamp and the nest form a part of a handling device, the so-called handler. Usually, a test head is attached to the handler, by means of which test-head the incoming signals are evaluated, and a decision relating to the quality of the tested electronic components is made. The electronic components are contacted individually by means of a test socket or—if a carrier is used—in groups with one or several test sockets at the same time. In this process the contacts of the electronic components are pressed at a predetermined force against the test contacts of the test socket or test sockets.
It has been found out that the test contacts of the test sockets become dirty over time, e.g. as a result of deposits of tin and its oxidation, wherein the conductivity is reduced, and a meaningful testing of the electronic components becomes increasingly difficult. For this reason the test contacts need to be cleaned or exchanged at relatively short intervals.
For this purpose it is necessary to interrupt the testing, and for the test sockets to be deinstalled and often even dismantled. After the test contacts have been cleaned or exchanged, an assembling and a restarting of the test device take place in the reverse order.
Attempts have already been made to provide a cleaning device which, after testing has been taking place for a predetermined number of test procedures, automatically interrupts testing, moves to the region of the test socket, and mechanically cleans the test contacts, for example by means of brushes. However, in this method, too, the actual testing of the electronic components needs to be interrupted, and consequently the average cycle time is prolonged.
Likewise, so-called cleaning dummies have already been used. These cleaning dummies have the same shape as the electronic components to be tested. However, instead of contacts, components with a cleaning function are provided. Because of the small amount of relative movement between the parts that have a cleaning function and the test contacts of the test sockets, the cleaning effect can only be assessed as being minimal. Therefore it is very often necessary to incorporate such cleaning dummies in the test procedure and in this manner prevent deterioration of the test results. Likewise, there are very limited possibilities for retrofitting cleaning dummies to older handlers, because these older devices are not able to distinguish the cleaning dummies from electronic components to be tested. In this approach, too, the average cycle time is prolonged.
US 2011/0132396 A1 discloses a cleaning material for cleaning contact elements and carrier structures of test interfaces, for example of test sockets, which are used for functional tests of semiconductor components. The cleaning material comprises a cleaning layer, beneath which several intermediary layers are arranged that support the cleaning layer. By means of the cleaning material it is possible to remove dirt build-up from the contact elements and from the carrier structures.
DE 10 2008 029 129 A1 discloses a contacting device for contacting electronic components, in particular ICs, by means of contact springs of a contact socket. A belt cleaning device with a belt movement mechanism and a cleaning belt is provided, which cleaning belt is guided over the contact springs of the contact socket. The cleaning belt comprises at least one recess, through which a component can be fed, and at least one cleaning region, which on its side facing the contact springs comprises an adhesive layer.
US 2007/0205753 A1 discloses a method for cleaning contact pins of an automatic test device, wherein a replacement cleaning device is inserted in a test socket in order to clean the contact pins by means of a cleaning agent.